Rewind like 5 years no one was thinking much about a11y, developers I mean but developers were doing a lot of js on the dom dom has a simple API - hasAttribute, getAttribute, setAttribute and it has this one very special attribute 'class' which is a space delimited series so that was a big pain in the ass if you want to say 'does it have this cl…

tokenListFor

HTMLElement.prototype._tokenListFor = function(attr) {
    var el = this,
        getTokens = function() {
            return (el.hasAttribute(attr)) ? el.getAttribute(attr).split(' ') : [];
        },
        tokList = {
            contains: function(token) {
                var contains = getTokens().some(function(item) {
                    return item === token;
                });
                return contains;
            },
            add: function(token) {
                var refs = getTokens();

                if (!this.contains(token)) {
                    refs.push(token);
                }

                el.setAttribute(attr, refs.join(' '));
            },
            remove: function(token) {
                var refs = getTokens().filter(function(item) {
                    return item !== token;
                });
                el.setAttribute(attr, refs.join(' '));
            }
        };
    return tokList;
};